Beijing - Olympics chief Thomas Bach said on Friday he favoured life bans for drug cheats, lamenting that current laws made such hardline measures impossible to execute.
Asked about a possible scenario of the twice-suspended Justin Gatlin winning the 100m world title in Beijing this weekend, Bach avoided direct reference to the controversial American but made his feelings clear on the doping scandal engulfing athletics.
"If you ask me about my emotions, I would say clearly, yes, I would still support a lifetime ban," the International Olympic Committee (IOC) president told a news conference on the eve of the championships.
"But legally it's just not possible. A lifelong ban would not stand any kind of (legal) challenge so we have to accept that," he added.
"As for (Gatlin), if you have an athlete who has served his suspension then he has the right to compete. It's a legal question not to be able to take stricter sanctions, a question of human rights."
Bach pointed to the so-called Osaka Rule implemented by the IOC in 2008 and banning athletes from competing at the next Olympics if they had been suspended for six months or longer, which was subsequently overturned in court.
"We made an effort and again we lost the court case," said Bach.
"The suspension is there and afterwards we have to treat those athletes in the same way as the others."
The spectre of doping hangs over the world championships after claims data from 12 000 blood tests between 2001 and 2012 revealed an "extraordinary extent of cheating" and that 50 Olympic and world gold medals could be tainted by drug use.
The International Association of Athletics Federations (IAAF) has stringently denied accusations it failed to follow up on suspicious test results and suspended 28 athletes last week after samples from the 2005 and 2007 world championships were retested.
They have yet to release the names of those implicated but Bach warned against making unfounded allegations.
"It's too early to speculate about results," he said.
"(World anti-doping agency) WADA and its independent commission very clearly said that before 2009 - before biological passports were introduced - none of the results contained in databases could be used as proof of doping.
"They could only serve as indication for target testing and the IAAF has explained to us that it has followed up with target testing."
Bach also lent his support to newly elected IAAF president Sebastian Coe's tough anti-doping stance.
"Seb Coe and I started with the fight against doping in 1981 as athletes in the Olympic congress in Baden Baden where we were asking for lifelong bans," said Bach, a former Olympic fencer.
"I am absolutely sure the IOC and the IAAF with president Coe will work very, very closely in a zero tolerance policy to protect clean athletes."
Meanwhile, departing IAAF chief Lamine Diack cut a forlorn figure as his presidency came to a close with yet more questions about doping.
"We're working on it," he snapped. "Claims we've done nothing are ridiculous and hardly deserve an answer. If you think one positive result is more important than a thousand negative results then I can't help you."